Process of regenerating used cooking fats



Patented Nov. 11, 1930 UNITED STATES PATENT OFFICE f MILLARD BRANDT, OF TAMAQUA, PENNSYLVANIA, ASSIGNOR TO DARGO CORPORA- TION, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE PROCESS OF REGENERATIN G USED COOKING FATS R0 Drawing.

This invention relates to processes of regenerating used cooking fats; and it comprises a process wherein used cooking fats and oils, such as lard, lard substitutes. olive oil, etc., are purified and regenerated for reuse by filtering the same through a body of coarse-grained activated carbon maintained at water bath temperature; all as more fully hereinafter set forth and as claimed.

In household and restaurant cooking, many kinds of fats and oils such, for instance, as lard, butter fat, olive oil and the various proprietary cooking fats and oils,

are used for frying and doughnut making and other varieties of deep fat drying. Often, as in making Saratoga chips, the quantity of oilused in a cooking operation is rather large and reuse is sometimes impracticable. In any event, these fats cannot be reused for any length of time. Sometimes the used and spoiled oils and fats can be sold as soap fat; but commonly they are simply discarded. In the interest of economy, it is desirable to provide a simple and ready way of regenerating these fats and oils after being used once or several times, restoring to the oils and fats their original quality; freeing them from odors and tastes developed in use. It is desirable also to get rid of .the brown coloration developed. Offensive odors of acrolein must be effectually removed. It is the object of the present invention to provide a simple apparatus for and method of regenerating these used fats.

I have found that a firm-grained activated carbon in rather coarse granular form can "be effectively used for this purpose. The carbon must be free of the very fine material which forms the greater part of commercial decolorizing carbons. A desirable carbon for the present purposes may be obtained by following the procedure of the Mumford Patent 1,286,187 or in other ways. I have found that any of these cooking fats and oils passed through this type of carbon at water bath temperatures, are effectually purified and given their original quality, even where the contamination in cooking has been far-going.

There are certain mechanical difiiculties, however, in so filtering these fats through this Application filed October 25, 1926. Serial No. 144,037.

carbon and in the present invention I have provided a means of overcoming these difficulties and of enabling utilization of the carbon for thedesired purpose; providing a simple and handy device enabling household the carbon body is a canvas layer. The outer metal casing or container forms an annular channel aroundthe inner. The inner casing is considerably shorter than the jacketing member so as to leave a rather considerable chamber below it. The outer meta-l container functions as a water bath and has a flat bottom so that it can be placed on an ordinary stove and readily heated. On putting water in the outer shell and placing the whole on a stove, the system becomes heated. Melted fat can now be poured through the body of carbon. A single passage brings the fat out with the original quality as regards color, tas'e and odor. Sometimes it is improved. If desired, fats heavily contaminated may be allowed to stand in contact with the carbon for a time but this is rarely necessary or desirable. After use as the body of carbon s'lands exposed to air it takes up oxygen and exercises oxidative action on adsorbed coloring matters and impurities, so that the device is long-lived.

In the accompanying illustration I have shown, more or less diagrammatically, one embodiment of this invention; the showing being a vertical section of a complete apparatus. In this showing, element 1 is a vertical metal casing having a flat bottom 2 adapted for stove heating. The casing may be of any suitable'metal, but tinned iron is generally employed. From the top of the container depends a receptacle 3 containing a body of coarse-grained carbon4. The receptacle has a perforated false bottom 5 supported on ring 6. Above the false bottom and-supporting the carbon is a layer of canvas or the like 7. A layer of sand 7 may be interposed between the canvas and the body of carbon. Below the false bottom is a sloping bottom 8, leading to a spout member 9 extending through the walls of container 1. It may be provided with a spigot or tap 10. The receptacle 3 being somewhat smaller in diameter than the container 1, there is an annular passagell therebetween, which serves as a steam or hot water space, 10 as the case may be. This space is open to the air through vents 12. Instead of using these open vents 12, a valved vent 13 may be employed where for any reason (such as high altitude) a little pressure is required in main- 15 taining a temperature of about 212 F.

In the use of this device, it is filled or partly filled with water and placed on a stove until the water is hot and the carbon heated thereby. The used cooking fat is then poured through the granulated carbon. After the filtration, the device is placed to one side exposed to air until its functions are again required. The activity of the carbon is as stated indefinitely long. It is a useful expedient however from time to time to allow the device to stand on the stove hot, but without passing fat through it. Under these circumstances, oxidation is accelerated and the odorous and color-giving bodies taken up by the carbon largely disappear by aerial oxidation,

The structure shown I regard as the best embodiment of my invention now known to me as regards simplicity and convenience;

but other and equivalent means may be employed for holding the carbon and keeping it hot during use.

What I claim is In periodic regeneration of cooking fats 40 and oils by means of active carbon, the process which comprises percolating a batch of used fat or oil in the liquid state through a body of coarse-grained, highly activated, adsorbent carbon, maintaining the carbon during said percolation at a temperature near that of boiling water, then exposing said carbon to the air while at about the same temperature and thereafter percolating therethrough another batch of used fat or oil.

In testimony whereof, I have hereunto affixed my signature.

MILLARD BRANDT.

Gruted Nova-her It, 1930, to

' Pltent No. 1,781.6.

IILLARD BRANDT.

It is hereby certified the! error lWQlfl ll the above lnobered pltclt requiring correction as loilowe: Page 1, in the heading to the primed apeelfleltioe. line 5, ltrilte out the worth "No drawing".

The dt'lwing coutliniu the figure In lion beioyv should be inert a part at the patent;

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Signed and relied this 2nd duy 0| December,

Acting fi mmt'ssioner nt htentst 

